WOAH sets first African swine fever vaccine rules

In May 2025, the World Organisation for Animal Health adopted their first international standard for African swine fever vaccines. With this recognition, the global swine health community has formally acknowledged the role that ASF vaccines may play in controlling and mitigating the disease. This is a major step forward, as WOAH standards are the basis for regulations recognized by the World Trade Organization for international trade in animals and animal products. These standards directly shape countries’ import and export regulations.

The Swine Health Information Center is pleased to share this update provided by Andres Perez and Rachel Schambow from the University of Minnesota College of Veterinary Medicine, Center for Animal Health and Food Safety.  

Following the adoption of the standard, several countries asked WOAH to provide guidance for evaluating ASF vaccines in the field. In July 2025, WOAH convened a panel of experts from different regions and specialties to develop a set of guidelines. Perez served as a member of this WOAH ad hoc Group on ASF Vaccines: Field Evaluation and Post-Vaccination Monitoring. The first version of the guidelines developed by the panel has recently been released. 

Key points from these documents and relevant scientific publications include:  

1. Current ASF vaccines use live attenuated (modified live) strains of the virus and are not inactivated or killed. This means some virus shedding is expected from vaccinated animals, and adverse side effects are possible. Countries will need to evaluate these potential adverse effects against the potential benefits of using vaccines. 
2. Due to virus shedding, the nonspecific clinical signs of ASF, and the absence of a serological test to differentiate vaccinated from infected animals, it may be challenging to define what constitutes an ASF case during vaccine evaluations or implementation.